The invention relates to image display, and in particular to display methods for high dynamic range image.
The dynamic range of a scene is expressed by the contrast ratio between its brightest and darkest parts. A low dynamic range image (LDR image) can be displayed on a standard display device because of its smaller dynamic range. Due to the range limitations of LDR images, LDR images cannot represent abundant brightness of real scenes properly. Thus, high dynamic range (HDR) images are necessary. A high dynamic range image (HDR image) is typically generated by combining multiple LDR images of the same scene taken with different exposures. High dynamic range images are broadly employed in image processing systems. Rather than being displayed on a standard display device directly, high dynamic range images require a translation from high dynamic range to low dynamic range for display.
Conventionally, an image panel and histogram panel are arranged on a display device, such as a screen, to display images and corresponding histograms. The conventional histogram panel can only display the brightness of low dynamic range data of the image pixels. FIG. 1 is a diagram of an embodiment of a conventional histogram panel. The conventional histogram panel 5 can only display the brightness of low dynamic range data of the image pixels. Thus, if an image processing system processes high dynamic range images, some image parts cannot be displayed by the conventional histogram panel 5 because of the out-of-range brightness.
For example, if an image processing system comprises an image panel and a conventional histogram panel 5 as shown in FIG. 1, an HDR image may be displayed in the image panel and the brightness data of the image pixels is displayed in the corresponding conventional histogram panel 5. When the displayed image is modified, the histogram panel 5 will be difficult to reflect the actual transformed result due to limited input range of histogram panel.
Thus, methods and interfaces for high dynamic range image display are desirable.